Tension spring is a coil spring that receives the axial pulling force, and the hook forms in the form of a side hook tension spring, a long hook tension spring, an English hook tension spring, a German hook tension spring, a semicircular hook tension spring, a duckbill hook spring, and the like. "Hook" is used to ensure the tensile force of the tension spring.Tension springs are widely used in medical respiratory equipment, motion control, medical mobile equipment, hand tools, home care equipment, shock absorption, pump springs, mechanical and electronic protective hardware, fluid control valves, mechanical aerospace components, actuators, switchgear In the machine and instrument.